Opened 5 years ago

Closed 5 years ago

# Polytopes normaliz backend doesn't handle a polytope with a trivial integral hull

Reported by: Owned by: tscrim major sage-8.0 geometry mkoeppe Travis Scrimshaw Matthias Koeppe N/A aa9f258 aa9f25855b6d72f7010c2f6241f0737d306b7237

### Description

Here is an example that is not handled properly:

```sage: ieqs = [[1, 2, -1, 0], [0, -1, 2, -1], [0, 0, -1, 2], [0, -1, 0, 0], [0, 0, -1, 0],
....: [0, 0, 0, -1], [-1, -1, -1, -1], [1, 1, 0, 0], [1, 0, 1, 0], [1, 0, 0, 1]]
sage: P = Polyhedron(ieqs=ieqs, backend='normaliz')
sage: P.bounding_box()
((-3/4, -1/2, -1/4), (-1/2, -1/4, 0))
sage: P.bounding_box(integral_hull=True)
(None, None)
sage: P.integral_points()
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
----> 1 P.integral_points()

/home/travis/sage-build/local/lib/python2.7/site-packages/sage/geometry/polyhedron/backend_normaliz.pyc in integral_points(self, threshold)
568         if threshold > 1:
569             box_min, box_max = self.bounding_box(integral_hull=True)
--> 570             box_points = prod(max_coord-min_coord+1 for min_coord, max_coord in zip(box_min, box_max))
571             if  box_points<threshold:
572                 from sage.geometry.integral_points import rectangular_box_points

TypeError: zip argument #1 must support iteration
```

### comment:1 Changed 5 years ago by tscrim

• Branch set to public/geometry/integral_points_empty_hull_normaliz-22938
• Commit set to aa9f25855b6d72f7010c2f6241f0737d306b7237
• Status changed from new to needs_review

New commits:

 ​aa9f258 `Fixing integral points for a non-empty polytope with trivial integral hull.`

### comment:2 Changed 5 years ago by mkoeppe

• Reviewers set to Matthias Koeppe
• Status changed from needs_review to positive_review

Thanks for fixing this.

### comment:3 Changed 5 years ago by vbraun

• Branch changed from public/geometry/integral_points_empty_hull_normaliz-22938 to aa9f25855b6d72f7010c2f6241f0737d306b7237
• Resolution set to fixed
• Status changed from positive_review to closed
Note: See TracTickets for help on using tickets.